For a considerably long time, automated transmissions have been used in different types of motor vehicles in the form of stepped and non-stepped or continuously variable transmissions. It is customary that, according to the operation point of the prime mover, such as the rotational speed, and the generated torque of the prime mover, an automated transmission determines the gear to be activated at the moment.
For better coordination of the transmission automatics, added parameters are partly used. By taking into consideration the temperature of the transmission and prime mover, it is possible to take into consideration increased inner friction, resulting from a cold engine and/or transmission oil and/or high rotational speeds of the prime mover, can be prevented by early shifting to a higher gear. When a driver's preference for an economical or sport driving style is determined or inquired, the switching points at which a change of gear or, in general, a change of the transmission reduction ratio is effected are changed so that at high or low engine rotational speeds, a call for a shift is initiated.
In the simplest case, the shifting points can be stored in the form of a table or characteristic field in an electronic building block of a control unit by which a target speed is coordinated with each operation point of the prime mover combined with the known driving speed of the vehicle, it is possible, when needed, to consider other parameters by increasing or reducing the values. To prevent a shift variation, the shifting points for changing to a higher gear and the shifting points for change to the previously activated lower gear are coordinated with different engine operation points.
Such transmission controls must be designed so that even on a steep uphill gradient and/or in a vehicle loaded to the admissible limit, the same as cold engine and transmission after a gear change, the prime mover can provide a strong enough torque to keep the vehicle speed constant at the selected transmission ratio and the given speed of the vehicle. Otherwise, after a shifting operation or a change of reduction ratio, an undesired delay of the vehicle would occur. Therefore, without taking into account other parameters, a transmission control has to be designed so that during acceleration of the vehicle, it is shifted to the next higher gear later. This results in an unnecessarily high fuel consumption, greater wear on the engine and transmission; the same as elevated noise emissions.
In order to guarantee reliable and comfortable operation of the vehicle, even on steep uphill gradients, and to reduce the effects of the disadvantages described, different known shift programs are provided for the automated transmission or the shift program are adapted or changed to satisfy the requirements on acceleration capacity, fuel consumption and noise emissions under different external conditions. In the simplest case, two shift programs can be available that are alternatively selectable by the driver where one is optimized for steep uphill gradients and the other for travel on level ground or in the downhill gradient. Other shift programs obviously can be designed and activated for driving in the downhill gradient or for different average or maximum uphill gradients. Of course, the added work load for the driver is problematic here because they, in addition, have to assess the zone in which the vehicle is driving and select a suitable shift program which, in the practice, as a rule, may be omitted or at least often leads to selection of a shift program that is not optimal.
DE 196 00 734 C2 discloses a method for controlling units and/or systems of a motor vehicle in which three essential kinds of data are distinguished as follows:                actual position determining data which is transmissible by way of telecommunication systems such as GPS data;        static data entrained in the vehicle in the form of digitalized road data, and        data derived by the driver-vehicle system such as transverse acceleration, differences of rotational speed of the wheels, yawing angles and driving direction.        
At least two of these kinds of data are converted to form a regulated variable for transmission control. With the aid of the actual data and the static data, it is particularly determined in what driving environment (city, country, expressway, level ground, uphill program) the vehicle is in and the shift program of a stepped or continuously variable automatic transmission of a motor vehicle is accordingly adapted and/or varied. In addition, other data can be used and/or other systems of the vehicle can be controlled.
This attachment makes an accurate and targeted influence of the switch points or of the shift program of an automatic transmission possible. For this, of course, at least actual position data is needed, for example, by way of a GPS system or digitized road maps entrained in the vehicle and preferably both kinds of data.
In the practical conversion, there are different problems concerning the electric and signal technology coupling of a GPS sensor with corresponding evaluation electronics and the wiring expenses related thereto and the need of carrying actual road maps of the area along on which the vehicle drives. It is true that navigational systems are increasingly developed in the vehicle and contain both kinds of data, but this is accompanied by a considerable expenses to ensure the compatibility of a transmission control with a great number of navigation systems existing on the market with different output formats and printouts. Moreover, a transmission control must also be fully capable of operating even without a working and active navigation system.
With this background, the problem on which the invention is based is to propose a method for influencing an automatic transmission, which is easy and does not require data exchange with devices outside the vehicle and independent of a digitalized road chart of the region on which the vehicle drives. At low construction expenses, it is possible to determine the amount of an external tractional resistance. Topographic information of the region must be obtained in which the vehicle drives which, if necessary, combines with other influencing variables, relative to the external tractional resistance of a tractional resistance detection unit, allows influencing the control of an automated transmission in a manner such that fuel consumption and the emission of pollutants and noises are reduced by moving the shifting points or selecting an adequate shift program. Moreover, the traveling comfort and the uphill gradient capacity of the vehicle are also to be improved.